1. Field of the Invention
The present invention relates to a component mounting apparatus for mounting components such as electronic components on a board such as a circuit board.
2. Description of the Related Art
Conventionally, an electronic component mounting apparatus has been so configured that components supplied from a supplying unit are taken out by being sucked with nozzles of a head, and conveyed onto a circuit board held by a circuit board holding unit, and then, mounted on the circuit board. The hold postures of the components sucked and held by the nozzles are inspected by an inspection unit provided on a moving path of the head, and based on the inspection results, the hold postures of the components are corrected as required and then a mounting operation is performed.
The head is provided with a plurality of nozzles. When the hold postures of the components sucked by the nozzles are inspected by the inspection unit, image information for each of the components sucked by the plural nozzles is not taken one by one and inspected, but plural pieces of image information for the plural nozzles, that is, plural pieces of image information for plural components are taken and inspected collectively by one sensor provided in the inspection unit so as to reduce the time required for hold posture inspection.
Further, when the hold posture inspection is performed to the components sucked by the nozzles, the head moves above the inspection unit. By using a line sensor or an area sensor with a shutter function, the hold posture inspection of the components sucked by the nozzles is performed in which the head is moving without being stopped above the inspection unit (hereinafter, an operation of taking image information of components sucked by the nozzles while moving the head without being stopped above the inspection unit and performing a hold posture inspection is called a scanning operation), whereby a time required for the hold posture inspection is reduced (for example, see Japanese Unexamined Patent Publication No. 1997-186492).
An exemplary operation of detecting an electronic component height in a conventional electronic component mounting apparatus will be briefly explained below with reference to FIG. 36.
An electronic component mounting apparatus 1020 shown in FIG. 36 is an example of a component mounting apparatus of a so-called robot type in which a head part with nozzles holding electronic components moves in X and Y directions to thereby perform operation from holding of components to mounting them on a circuit board 1008. The electronic component mounting apparatus 1020 includes: a supplying unit 1002 for supplying electronic components 1001; a head part 1004 with a plurality of mounting nozzles 1003 for taking out the electronic components 1001 from the supplying unit 1002; a recognizing unit 1005 for recognizing postures of the electronic components 1001 held by the mounting nozzles 1003 in a planar manner; an electronic component height detecting unit 1006, having a light emitting unit for emitting parallel luminous flux and a light receiving unit for receiving the parallel luminous flux, for detecting the heights of the electronic components 1001 held by the mounting nozzles 1003; a control unit 1007 for correcting the postures of the electronic components 1001 based on the recognition result from the recognizing unit 1005, and determining good/bad quality of the postures of the components 1001 based on the detection result from the electronic component height detecting unit 1006; and a robot 1009 for moving the head part 1004 in X and Y directions from the supplying unit 1002 to a component mounting position on the circuit board 1008.
Further, as shown in FIG. 37, a plurality of mounting nozzles 1003 are aligned in one row on the head part 1004, and the element component height detecting unit 1006 is arranged in an orthogonal direction to detection moving direction α of the head part 1004.
Hereinafter, an operation of detecting electronic component height in the conventional electronic component mounting apparatus 1020 will be explained briefly.
In order to take out the electronic components 1001, positioned at a suction position by the supplying unit 1002, by the mounting nozzles 1003 provided on the head part 1004, the head part 1004 is positioned by the robot 1009, and the mounting nozzles 1003 on the head part 1004 hold the electronic components 1001. Since the plurality of mounting nozzles 1003 are provided on the head part 1004 as described above, each mounting nozzle 1003 holds the electronic component 1001.
When the electronic component 1001 is held by each mounting nozzle 1003, each held state of the electronic component 1001 is confirmed in the planar manner, so the head part 1004 is positioned at a recognition position in the recognizing unit 1005 by the robot 1009.
The recognizing unit 1005 recognizes a planar condition of the electronic component 1001 held by each mounting nozzle 1003, and the control unit 1007 performs a positional correction of each component 1001 with respect to a mounting position based on the recognition result.
Next, in order to detect the electronic component 1001 in a height direction, each mounting nozzle 1003 of the head part 1004 is positioned by the robot 1009, and passes between the component height detecting units 1006 arranged opposite each other as shown in FIG. 37 along the detection moving direction α. At this time, each mounting nozzle 1003 passes orthogonal to the parallel luminous flux 1010 for detection emitted by the component height detecting unit 1006 in a state where the electronic components 1001 held are positioned at a detection height (for example, Japanese Unexamined Patent Publication No. 2000-278000). Based on image formed by the electronic component 1001 which is held by each mounting nozzle 1003 and detected by the component height detecting units 1006 when passing therebetween, the control unit 1007 performs a good/bad quality determination of the hold posture of each electronic component 1001. When the heights of a plurality of electronic components 1001 are detected continuously, each electronic component 1001 is determined separately by detecting a gap between adjacent electronic components 1001 held by each mounting nozzle 1003 by the component height detecting units 1006.
If the electronic component 1001 is determined as good in the control unit 1007, the head part 1004 is positioned at an electronic component mounting position on the circuit board 1008 by the operation of the robot 1009. On the other hand, if it is determined as defective, the head part 1004 moves to a disposal position (not shown) of the electronic component 1001, and the defective electronic component 1001 is disposed. In this way, the operation described above is repeated.
However, the conventional electronic component mounting apparatus had the following problems.
That is, when the inspection unit inspects the hold postures of components sucked by the plurality of nozzles provided on the head, pieces of image information of plural components are taken collectively by a single sensor of the inspection unit. At this time, since the hold posture inspection is performed with light beams emitted from lighting units provided in the outer periphery of the viewing range of the sensor taking the image information, that is, light beams of the same light amount set in the same manner are irradiated to the plural components at the same timing by the same lighting units, image information about the shapes of components can not be obtained clearly depending on the surface conditions, materials, colors and the like of components. Therefore, there may be a case of a combination of components in which the inspection accuracy in the hold posture inspection is not secured through one scanning operation, or a combination of components in which the hold posture inspection itself is impossible. In such the case, it is required to take in image information again by changing the setting of light beams irradiated from the lighting unit for the posture inspection of components in which inspection accuracy is not obtained or the inspection itself is not possible. Therefore, plural times of scanning operations must be performed, and a time required for the hold posture inspection increases. As a result, there is a case where the productivity in the electronic component mounting apparatus is reduced.
Further, since pieces of hold posture information of components sucked by a plurality of nozzles are taken collectively by the single sensor provided to the inspection unit, a field of view range of the sensor, that is, an angle of field of view, becomes large, whereby the resolution for one pixel of the sensor becomes rough, so a sufficient inspection accuracy cannot be obtained. As a result, there is a case where the productivity in the electronic component mounting apparatus is reduced.
It is therefore a first object of the present invention to provide an electronic component mounting apparatus capable of improving the productivity in the electronic component mounting apparatus.
Further, in the case of detecting the height of the electronic component as described above, the following problem exists. That is, if the mounting nozzles 1003 provided on the head part 1004 are aligned in one row, the operation of component height detection is performed by causing the mounting nozzles 1003 to pass between the component height detecting units 1006 once, along the detection moving direction α. However, in a case where the mounting nozzles 1003 are arranged in plural rows on the head part 1004 as shown in FIG. 38, if the mounting nozzles 1003 are moved in an orthogonal direction with respect to the parallel luminous flux 1010 emitted from the component height detecting unit 1006, images of plural electronic components 1001 are detected at once, so the detecting operation cannot be completed at one time, and the detecting operations must be performed for plural times corresponding to the respective rows.
In recent years, it is required to speed-up a cycle time in an electronic component mounting apparatus. Therefore, the number of mounting nozzles 1003 provided on the head part 1004 tends to increase, and also due to a decrease in the equipment size, an arrangement of the mounting nozzles 1003 in two rows is not unusual. In such a state, performing height detecting operations for the components 1001 for plural times prevents speeding-up of the cycle time.
It is therefore a second object of the present invention to provide a component mounting apparatus and a component mounting method executed in the component mounting apparatus, capable of speeding-up a cycle time.